The subject matter disclosed herein relates generally to gasification systems, and more particularly, to heat recovery systems for biomass gasification systems.
Gasification is a process that is often employed in various industries and applications for conversion of a lower, less readily usable type of fuel into a higher form of fuel. For example, biomass gasification systems are utilized in a variety of types of power plants to convert biomass into a more combustible form, referred to as producer gas. In some systems, the producer gas may be combusted by an engine to produce electricity. In other systems, the producer gas may be used to generate heat or to generate substitute natural gas (SNG).
Very generally, producer gas is a type of synthesis gas (syngas), formed by the relatively low temperature gasification of biomass, typically in the presence of air. The producer gas includes combustible gases, such as carbon monoxide, carbon dioxide, hydrogen, methane, and nitrogen, and can be combusted to generate power. Further, the producer gas can be utilized to make methanol, ammonia, and diesel fuel through known commercial catalytic processes. In such a way, various forms of organic waste, such as wood, coconut shell fibers, and alcohol fuels, may be gasified for use in the production of electricity for a variety of downstream applications. However, prior to use in a power generation system, the producer gas may need to be cooled to generate a gas mixture that has a temperature suitable for combustion. To that end, many current systems utilize a cooling and cleaning system to remove heat from the producer gas. However, this arrangement imposes a substantial cooling load requirement on the components of the cooling and cleaning system (e.g., scrubbers, filters, etc.), and the removed heat is often discarded as waste.